In certain applications of semiconductor technology it would be desirable to incorporate various high voltage components into semiconductor devices. In particular, semiconductor devices having both low voltage components and high voltage components in the same device may be useful. For example, it may be desirable to manufacture a semiconductor device such as an EEPROM including a high voltage capacitor and a high voltage diffuse MOS (DMOS) transistor.
Although it is desirable to have high voltage components in low voltage devices such as EEPROMs, one of ordinary skill in the art will readily recognize that there are drawbacks to doing so. In particular, processing methods for high voltage components may involve thermal treatments or other steps that adversely affect the fabrication of low voltage devices. In addition, portions of high voltage components may have requirements that may be incompatible with low voltage devices. For example, the insulator in a high voltage capacitor may be desired to have a breakdown voltage at or in excess of twenty-five or fifty volts. However, conventional low voltage devices such as EEPROMs utilize insulating layers having thicknesses that are insufficient to support such a breakdown voltage. In an EEPROM, for example, insulating layers have thicknesses that may be insufficient to provide the desired breakdown voltage for such a high voltage capacitor. Consequently, integrating high voltage components in a device utilizing processing techniques used in forming lower voltage may be problematic.
Accordingly, what is needed is a method and system for incorporating high voltage devices into processing appropriate for EEPROMs. The present invention addresses such a need.